Typographical machine



prifl i, 136. A. J. STOUGES 2937,99

TYPOGRAPHICAL MACHINE Filed May 19, 1933 Patented Apr. 14, 1936 UNITED STATES TYPOGRAPHICAL MACHINE Anthony J. Stouges, Queens Village, N. Y., as-

signor toMergenthaler Linotype Company, a corporation of New York Application May 19, 1933, SerialNo. 671,831

6 Claims.

This invention relates to means for preventing the adherence of molten metal to an object, and especially to means for preventing the adherence of molten metal to the plunger rod of machines designed to produce type bars, types, and like typographical elements.

In the operation of the casting mechanism of such machines, molten type metal contained in a so-called metal pot is ejected therefrom into a slug casting mold by means of a plunger operating in a Well of the pot, this plunger being carried at the lower end of a steel actuating plunger rod which extends upwardly through the bath of molten metal and which is connected above the pot to appropriate power devices adapted to move the rod down and up in successive slug casting operations.

' During the alternate down and up movements of the rod, a central section thereof is carried below and above the level of the bath, and, in practice, it has been found that when this central section of the rod is carried below the level of the bath molten metal adheres to it and that the metal which so adheres to the rod hardens on exposure to the air as this section of the rod is thereafter raised above the level of the bath. The metal which so hardens on the rod accumulates, in the repeated operations of the plunger, and forms a body or shell, particularly at the upper end of this section of the rod, which must be removed from time to time, otherwise it would accumulate to such proportions that it would cause splashing which, if permitted, would not only detract from the eflficiency of the slug casting operation but, in addition, it would endanger the operator and others who might be near the machine.

This accumulation of metal about the upper portion of the central section of the rod which is immersed in the bath during the casting operation is believed to be due to the fact that while the temperature of the exposed portion of the rod is high, by virtue of the lower end of the rod being immersed in the bath, yet the temperature of this central section, prior to its immersion, is so reduced by radiation as well as by conduction of heat therefrom that the molten metal is chilled as this section of the rod is immersed therein, and that when the molten metal is so chilled it adheres to the rod. Also it is believed that when this section of the rod is immersed in the bath, and the radiation losses are thus prevented, its temperature is raised sufficiently high to remelt the metal which so adheres to it except at and slightly below the level of the bath where the conduction losses to the exposed upper end of the rod are such as to prevent the temperature of the rod from being raised sufficiently high to cause the adhering metal to remelt.

In accordance with the present invention the metal does not adhere to it as it too is alternately I carried into and out of the. bath during the reciprocation of the plunger.

For a clearer understanding of theinvention, reference may be made to the accompanying drawing. In this drawing, however, the invention is shown merely in preferred form and by way of example, but obviously many changes and variations may be made therein and in its mode of application which will be comprised within its spirit. It should, therefore, be understood that the invention is not limited to any specific form or embodiment except in so far as such limitations are specified in the claims.

Referring to the drawing:

Fig. '1 is an elevational view, partially in section, of certain portions of a casting mechanism embodying the principles of the present invention; I

Fig. 2 is an enlarged view, in section, showing in detail the plunger, the plunger rod and the shield shown in Fig. 1, and

Fig. 3 is a plan View taken along the line 3--,3 of Fig. 2.

As shown, the casting mechanism comprises a metal pot l formed with a well I l therein, and having a discharge spout l2 leading from the well and adapted to deliver molten metal into a mold l3. The ejection of the molten metal from the pot is efiected by means of a plunger I4 movable down and up in thewell l I and operated by a plunger rod I 5 pivotally connected thereto at its lower end by a pin IS. The plunger rod I5 extends upwardly through the bath of molten metal, and it is pivotally connected at its upper end, by a pin H, to a lever l8 which comprises a part of actuating mechanism adapted to move the rod and the associated plunger down and up in successive casting operations.

As before explained, the molten metal in the pot in the operation of the plunger l4 ordinarily adheres to that portion of the rod which is alternately above and below the level of the bath, and the metal which so adheres to the rod, when brought into contact with the air, cools and hardens and rapidly builds up on the rod in the form of the objectionable body or shell, before alluded to.

According to the present invention, such accumulation of metal on the plunger rod is prevented, means of a shield 20 which surrounds at least that portionof the rod l5 which is in line with and slightly below the level of the bath when the plunger I4 is in its down posi tion. In the present embodiment of the invention the shield 20 is made of aluminum or other suitable metal or alloy having high heat con-ducting properties, and its outer surface tapers throughout its length from the top to the bottom where it terminates in a bulky shoulder 2| which fits tightly about the rod to establish good thermal contact as well as to prevent the passage of molten metal therebetween, and to prevent displacement of the shield it is secured to the'rod as by means of apin 23. The shield is so positioned on the rod that this bulky shoulder remains immersed in the bath when the plunger is in its raised position as indicated by the full lines in Fig. 1, and the length of the shield is such that the upper end thereof remains slightly above the level of the bath when the plunger is moved to its down position, as indicated by the dotted lines in the same figure. That portion of the shield above the bulky shoulder 2| is made relatively thin sothat it is highly responsive to temperature changes and it is separated from the rod by an air space 22 which serves to prevent the transfer of heat therebetween. V V

The bulky shoulder at the lower end of the shield being immersed, even when the plunger is in its normal raised position, absorbs heat from the bath as well'as from the immersed lower end ofthe plunger rod 'and it is, therefore, maintained at a temperature substantially the same as the temperature of the bath, but the relatively thin upper portion of the shield being exposed to the ambient atmosphere radiates heat and it is at'a temperature which gradually decreases towards the upper end from that portion which is in line with the level of the b'ath'and which is at a temperature substantially the same as the temperature of the bath, this gradual decrease in temperature, however, being slight due to the high heat conducting propertiesof the shield. Under these conditions, the temperature of this portion of the shield is elevated to substantially the temperature of the bath as it'isbrought into contact therewith when the plunger is moved to its down position with the result that the molten metal is not chilled enough to cause it to adhere to the shield, this increase in temperature being due primarily to the high degree of response which the thin wall of the shield has to temperature changes and to the fact that as the shield is immersed its heat absorbing area increases and its heat radiating area decreases accordingly.

While the above arrangement is successful in preventing metal from accumulating on the rod l5 as well as on the shield ZOduring successive casting operations it has been found that when the bathis permitted to solidify after a casting operation and then rendered molten prior tothe neat casting operation, metal is likely to adhere to that portion of the shield which is in line with and slightly below the level of the bath when the plunger is in its normal raised position. In the present embodiment of the invention, however, metal which so adheres to the shield is removed as it is immersed into the bath when the plunger is moved from its normal raised position to its down position, this being due to the fact that while the shield is being so moved its temperature as well as the temperature of the adhering metal is raised sufficiently high to create a slight degree of melting therebetween, and when this is brought about the metal easily drops from the tapering outer surface of the shield.

I claim:-

1'. In a typographical machine, the combination of a pot containing a bath of molten metal, a reciprocable plunger rod positioned in the pot, and a metal shield so positioned about the rod that thelower end thereof remains below the level of the bath and the upper end thereof remains above the level of the bath during the reciprocation of the rod, said lower end being secured directly on the rod and the remaining upper portion of the shield being spaced from the rod and of such thinness that its temperature is raised to substantially the temperature of the bath as it is brought into contact therewith.

2. In a typographical machine, the combination of a pot containing a bath of molten metal, a reciprocable plunger rod positioned in the pot, and a metal shield so positioned about the rod that the lower end thereof remains below the level of the bath and theupper end thereof remains above the level of the bath during the reciprocation of the rod, said lower end beingsecured directly on the rod and that portion of the shield in line with the level of the bath when the rod is in its down position being spaced from the rod and of such thinness that its temperature is raised to substantially the temperature of the bath as it is brought into contact therewith. i

3. In a typographical machine, the combination of 'a pot containing a bath of molten metal, a reciprocableplunger rod positioned in the pot, and a metal shield so positioned about the rod that the lower end thereof remains below the level of the'bath arid a central section thereof is alternately carried below and above the level of the bath during the reciprocation of the rod, said lower end being mounted directly on the rod and said central sectionbeing spaced from the rod and of such thinness that its temperature is raised to substantially the temperature of the bath'as it is brought into contact therewith.

'4. In a typographical machine, the combination of a pot containing a bath of'molten metal, a reciprocable plunger rod positioned in the pot, and a metalshield so positioned about the rod that the lower end thereof remains below the level of the bath anda central section thereof is alternately carried below and abovethe level of the bath during the reciprocation'of the rod, said lower end being mounted directly on 'the rod and said central section being spaced from the rod, tapered inwardly from the top to the bottom thereof and of such thinness that its temperature is raised to substantially the 'temperature of the bath as it is broughtint'ocontact therewith.

5. In combination, apot containing a'bath of molten metal, a reciprocable plunger rod positioned in the pot, and-a metal shield sopositioned about the rod that the lowerend thereof remains below the level of the bath "and the upper end thereof remains above the level of the bath during the reciprocation of the rod, said lower end being bulky and secured to the rod and the remaining upper portion being relatively thin and spaced from the rod.

6. In combination, a pot containing a bath of molten metal, a reciprocable plunger rod so positioned that the lower end thereof remains below the level of the bath and a central section thereof is alternately carried below and above the level of the bath during the reciprocation of the plunger, and a metal shield having a section of relatively great mass which surrounds and which is secured to said lower end and a relatively thin section which surrounds and which is spaced from said central section.

ANTHONY J. STOUGES. 

